Substituted poly aralkyl alkylene poly amino poly acetic acids and salts



Patented Jan. 6, 1953 UNITED STATES PATENT OFFICE SUBSTITUTED POLY'ARALKYL ALKYLENE POLY AMINO POLY ACETIC ACIDS AND SALTS Frederick C. Bei'sworth,-Verona,=N.

No Drawing: Application November 1, 1950, Serial No. 193,545

This invention relates to metal ion chelating compounds for use in aqueous solutions and has for its object the provision of a metal ion chelatingcompound which is utilizable inacid as well as alkaline'pI-I solutions.

A further object is to provide a bactericidally active metal ion sequestering agent.-

Still another object is to provide a metal ion sequestering 'agent that is particularly effective toward poly-valent heavymetals and metals of the so-called transition 'group'of metals consisting of copper, nickel, cobalt, and the like.

Other objects will be apparent as the invention is more fully disclosed.

In accordance with these objects, I have discovered that substituted poly alkylene polyamine polyacetic acids corresponding to the formula:

where 11:1, 2, 3, 4; X=hydrogen, alkyl, halogen, hydro'xyl of alkoxyl; alkyleneze'thylene, propylene, trimethylene, and R is a (CHzM group wherein n is a numeral of the group consisting of l to 5, arehighly water soluble'bactericides and fungicides havinga strong sequestering power'for metal ions (particularly the transition metals) inaqueous solution. The alkali metal salts are amino-acids themselves are reactive toward such metals assCu,v Co, Ni, etc.,' i. e., the metals. are che'latedlin acid .as'well asalkaline :solutions. X

the most. powerful sequestering agents, "but the They are'excellent as reclaiming agents for natural-and' synthetic rubber being soluble in such rubber products and active to remove the vulcanization'metal catalyst in non-ionic form. The

chelates themselves: may be used to introduce a desired metal into the: plastic mixture to act as inhibitors aligo dynamic catalyst when so'activated by temperature or working pressure, etc. The compounds are especially useful as oil additives-both peraseand in form of chelates to either act as emulsantviscositycontrol and/ or as aid in lubrication' orIcombustion Of the com-.

pounds specifically disclosed, it was found that the bactericidal and fungicidal activity was greatest when both halogen and hydroxyl groups were present on the aromatic ring. This and their I varying solubility in'water and emulsion makes them desirabl' adducts to metal working emulsion type of lubricants as antobiotics. The amine salts are'- more' soluble in organic systems than are the alkali metal salts although the potassium salts showremarkable solubility in polar solvents.

Example I Two moles. of 4-hydroxy-2,6-dichlorobenzyl chloride are reacted with one mole of diethylene triamine in aqueous ethanol by the gradual addition of an ethanol solution of the halide to the amine; the reaction mixture being maintained at vigorous refiux. The addition is .made over a period of 3-4 hours and thereaction is completed by reflux for an additional hour. The product is mainly (about 75%) the dihydrochloride of the following base:

In general, the sequestering action with alkaline" earth ions is relatively weaker compared-toxsuch reagents as ethylene diamine tetraacetic':

acid, and these compounds are less useful for simple water softening. However, their high affinity for the transition metals render them effective antioxidantsjinuaqueous solution, or inmaterials which are to be used in or with.. water such as for instance bar soap with which they are. highly compatible and .perform multifunctional i. e.,.are anti-oxidants. over longperiod of storage, protect the soap against water hardness when used and being germicidally and fun gicidally active, tend to sterilize when used? They are excellent adducts to elastomers both syn= thetic and natural and act as plasticizers and accepters and inhibitors of detrimental metal ions.

To obtain the free base of the compound, the reaction mixture istreated with 2 moles of sodium hydroxide and agitated until all chloride ion is reacted to form sodium chloride. This is filtered off as it is precipitated and the final filtrate may 'be'vacuum dried and the organic free bas extractedwithalcohol to obtain aproduct' practically free from inorganic salt. The result' ing. diethylene triaminexderivative is dissolved in anhydrous ethanol and is carboxymethylated in accordance with the carboxymethylationreaction described in my Patents Nos. 2,387,735, 2,407,645and 2,461,519, using 3 moles of sodium cyanide'and 3 moles of CHzO and maintaining alkaline conditions in the reaction solution. The carboxymethylation reaction proceeds smoothly with good agitation at a reaction temperature of 2,624,769 3 about 100 C. The resulting carboxymethylated Example IV product is the trisodium salt of di-(2,4-dichloro- 4-hydroxy benzyl) -diethylene triamine triacetic similarly the process of Example I was found acid having the formula: satisfactory for the synthesis from p-chloro- CHa-CO 011 I CHa-COOH CHQ'COOH It may be obtained as the crystalline sodium salt phenylpentylchloride and diethylene triamine of by evaporation of most of the water and adding the amino acid having the formula:

CHz-COOH GHa-COOH CHz-COOH alcohol suflicient to provide about a 50/50 alco- This substance is somewhat less water soluble hol-aqueous solution. than the product of Example I but it is more sur- The free amino acid is obtained by acidification face active as well as having the other desirable of the reaction solution with a mineral acid (such properties of the products of this invention.

as HCl), evaporating to dryness, and leaching The polyalkylene polyamine bases employed in with warm absolute ethanol. The purified amino the above examples are generally recognized by acid may be isolated in crystalline form relamembers of the general class of compounds extively free from inorganic salts by evaporation of pressed by the formula:

the extract NI-I2-(alkyleneNH) n-alkylene-NH2 Example H where n is a small integer. The bases of thi type I have found that dipropylene triamine may be in which n varies from one to four inclusive are substituted for diethylene triamine in Example I well known, and the ethylene and propylene bases to give a product having the formula: are readily available commercially. I have found CHa-COOH CHa-COOH CHa-COOH 01 1 The methyl group increases the solubility of the that such polyethylene bases may be used as subamino acid in organic solvents. stantial equivalents for those in the examples I have found that the process of Example I above, the products having in general the expectmay also be used to prepare similar chelating ed structure. I have found for example, that the agents in which the substituents on the ring, the use of tetraethylene pentamine in place of dilength of the chain (R) between the ring and ethylene triamine of Example I produces a simithe amino groups; and the alkylene groups are lar bactericidal and fungicidal chelating agent varied. which is water soluble. Thus far I have failed to El'ample 111 obtain the amino acid in pure form, although its alkali metal salt is a crystalline material. This is Thus. the of chlomde as probably due to impurities resulting from side rethe hahde and dl'tnmethylene tna'mme actions in the substitution of the polyalkylene polyamine with the alkyl halide to give some sub- CH2.CH2.CH2 NH2) stitution on the secondary nitrogens of the polyamine. The product, however, was a powerful as the base resulted in the formation of an chelating agent and contained five acetic acid analogous amino acid which must have the groups after carboxymethylation. It is believed formula: that a large proportion of the reaction product I I HO-O-CHr-N-Cliiz-CHrCHs-N-GHr omcm-IL-om-Qon The water solubility of this compound and its consists of the analogous compound having the metal chelates is somewhat greater than that of formula:

the halide derivatives described in Examples I CHTCOOH and II. Further, this substance is a useful inter- 5 C1 mediate for the further substitution of halo en 6 I 4 in the aromatic ring, to give from 1 to 4 halog ens HO in the positions. When two halogens are intro- 1 C1 duced it is believed that they are attached at the The reaction of the dialkylene triamine positions marked by X. lates was found to involve a 1:1 combination of X CHI'COOH x 5 heavy metals to give chelates having the formula:

This accounts for the sequestering action of the amino acid for divalent metal, and the free saltforming acetic acid group apparently accounts 10 for the solubility of the metal chelate in water. I have also found that the compounds of the present invention which are derived from the higher polyalkylene polyamines sequester more than one mole of metal per mole of chelating agent. For example, it was found that a single disubstituted triethylene tetraamine tetraacetic acid combined with two moles of copper ions to give an inner complex salt presumably having the following structure:

Although the structure given here shows that all salt forming (solubilizing) groups are neutralized, forming non-ionic chelate, they do not precipitate in alkaline solution. It appears that formula:

OHTC 0 on O'Hz- 00 OH CHa-CO OH wherein a is a numeral of the group consisting of 1 to 5; alkylene is one of the group consisting of CH2'CH2, CH2-CH2'CH2 and CH(CH3) 'CHZ; X is one of the group consisting of hydrogen, alkyl, alkoxyl, hydroxyl and halogen with one to three k X being halogen, and n is a numeral selected from the group consisting of 1 to 4.

2. The compound conforming to the structural formula:

CH2-C O OH 01 CHz-COOH OHz-COOH 3. The compound conforming to the structural formula:

CH2 0 0 OH CH2-COOH CHa-COOH secondary salt formation occurs, probably a phenolate.

Having hereinabove described the present invention generically and specifically and given sev- Sl THz-COOH I HOG-cm NCHz-CH: --NOH@ 4. The compound conforming to the structural formula:

CH2-CO OH CHa-GOOH CHz-COOH 5. The compound conforming to the structural formula:

FREDERICK C. BERSWORTH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 868,294 Schmidlin Oct. 15, 1907 932,266 Fussenegger Aug. 24, 1909 2,195,974 Reppe et a1. Apr. 2, 1940 2,489,363 Bersworth Nov. 29, 1949 FOREIGN PATENTS Number Country Date 18,095 Great Britain of 1913 642,244 Germany Mar. 6, 1937 OTHER REFERENCES Alphen: Chem. Abs., vol. 38, col. 4943 (1944). 

1. THE COMPOUND CONFORMING TO THE STRUCTURAL FORMULA: 